Although photo-sensitive silver halide photographic material is well known for its capability of giving especially excellent image quality and sensitivity, there is still a demand for further improvement in its image quality.
Among important factors relating to the image quality, there can be mentioned two, that is to say, color reproducibility, which is an ability to what extent the colors contained in the original can faithfully and vividly be reproduced, and sharpness, which gives a great effect on vividness and impression of three-dimensional depth of the produced image, to be essential.
For the improvement of the color reproducibility, many other requirements must be satisfied and, among these requirements, spectral sensitivity in the case of the photo-sensitive materials for printing use is important.
In this respect, in the case of high silver chloride-containing type color paper, silver chloride is especially advantageous for the reason that it has no effective spectral absorption in the visible spectral region and, for this reason, the inherent sensitivity does not injure distinguishability with respect to red-sensitivity, green-sensitivity and blue-sensitivity, i.e., no color contamination is brought about.
On the other hand, in order to improve sharpness, various attempts have been made, and it is known in the art that a technique of incorporating a white pigment into photo-sensitive printing materials for image appreciation works for the improvement of the image sharpness.
Since it is known that increasing incorporation of a white pigment improves image sharpness. In general, various technical attempts to incorporate this at a higher content in the photo-sensitive materials have been made in the art.
For example, Japanese Patent Publications Open to Public Inspection (herein after referred to as "Japanese Patent O.P.I. Publication") Nos. 55-113039(1980), 55-113040(1980) and 57-35855(1982) disclose a technique of modifying a white pigment by the use of certain kinds of amine compounds, -diketone chelating compounds and polyhydric alcohols to improve dispersibility:
Further, Japanese Patent O.P.I. Publication Nos. 57-151942(1982), 58-111030(1983) and 58-7630(1983) disclose a technique of incorporating the white pigment at a higher amount by treating the surface of the pigment with certain kinds of alkyl titanate, and organopolysiloxane.
On the other hand, manufacturers of the photographic materials have been requested by their users to provide these materials at lower cost.
For this reason, improved productivity of the materials has been a long-felt demand in the relevant field of the art.
For the purpose of improving efficiency of the productivity of the photographic materials, various attempts have been made by the manufacturer. Among these attempts, enhancement of coating speed, by which photographic layers including a silver halide emulsion layers are provided on a support and which can directly lead to the improvement of productivity of the materials, has always been a demand assigned on the manufacturer.
However, coating the photographic layer at very high speed uniformly and without causing any defects is not a very easy task for the manufacture. For with increasing the coating speed, troubles such as due to streaking or lack of uniformity become more likely to take place, which hinders speeding up of the coating rate.
Recently, demand for large size print has become larger and even a tiny coating defect, which had not become a subject for trouble, has become a matter of concern in a large size photo-printing paper because it is conspicuous.
It has been known in the art that these coating characteristics are largely dependent upon the component of the silver halide emulsion coating liquid or quality of the support upon which the emulsion is to be coated. Further, it has also been known in the art that non-uniformity is likely to take place after developing process in a photographic material in which high chloride-containing silver halide emulsion is employed. In view of the state of the art mentioned above, overall improvement has been requested.